Studies on the Peripheral Circulation and Metabolism in Man IV. Oxygen Utilization and Lactate Formation in the Legs of Healthy Young Men during Strenuous Exercise

Pernow, B., J. Wahren and S. Zetterquist. Studies on the peripheral circulation and metabolism in man. IV. Oxygen utilization and lactate formation in the legs of healthy young men during strenuous exercise. Acta physiol. scand. 1965. 64. 289–298. – 19 healthy young men exercised on a bicycle ergometer with increasing work loads. From indwelling catheters in the brachial artery and the femoral vein blood samples were drawn before, during and after exercise. The a–v O2 difference in the leg increased linearly in relation to heart rate and O2 uptake to a mean value of 163 ml/1 at maximal work. At this intensity (heart rate 180–195 beats per min) the mean value of the venous O2 saturation was 9 per cent. A linear relationship existed between log lactate and heart rate during work as well as between log lactate and O2 saturation of the femoral venous blood. The slope for the semilogarithmic regression of the femoral venous concentration of excess lactate (XL) on heart rate was significantly steeper than that of venous total lactate concentration. pH of venous blood decreased during exercise to a mean value of 7.09 at maximal load. A linear relation was obtained between decrease in pH and increase in lactate. The reproducibility of the abovementioned results was evaluated for 6 subjects. A comparison between exercise performed with one and two legs showed that heart rate increased almost identically in relation to O2 uptake at both types of exercise. The venous O2 saturation was somewhat lower at submaximal work loads during one‐leg exercise, while the final venous O2 saturation values at maximal work were almost identical. Lactate increased more rapidly during one‐leg exercise. These data seem to indicate that blood flow in relation to O2 demand is less adequate in one‐leg than in two‐leg exercise at comparable working intensities.